Subscription radio company SiriusXM says it's buying music streaming service Pandora Media in a stock deal valued at about $3.5 billion that'll allow it to expand its service beyond cars and into homes and other mobile areas.

SiriusXM Holdings has more than 36 million subscribers in North America, while Pandora has more than 70 million monthly active users.

Pandora stockholders will receive 1.44 newly issued SiriusXM shares for each Pandora share they own. Pandora has a "go-shop" period in which it can solicit other offers from third parties.

Both companies' boards have approved the transaction, which is expected to close in 2019's first quarter. It still needs approval from Pandora shareholders.